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author | npiggin@suse.de <npiggin@suse.de> | 2010-05-27 01:05:33 +1000 |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2010-05-27 22:15:33 -0400 |
commit | 7bb46a6734a7e1ad4beaecc11cae7ed3ff81d30f (patch) | |
tree | e575d9c55e2a6ccc645dcb3ae2564de458b428f2 /include/linux/fs.h | |
parent | 7000d3c424e5bb350e502a477fb0e1ed42f8b10e (diff) | |
download | kernel_samsung_espresso10-7bb46a6734a7e1ad4beaecc11cae7ed3ff81d30f.zip kernel_samsung_espresso10-7bb46a6734a7e1ad4beaecc11cae7ed3ff81d30f.tar.gz kernel_samsung_espresso10-7bb46a6734a7e1ad4beaecc11cae7ed3ff81d30f.tar.bz2 |
fs: introduce new truncate sequence
Introduce a new truncate calling sequence into fs/mm subsystems. Rather than
setattr > vmtruncate > truncate, have filesystems call their truncate sequence
from ->setattr if filesystem specific operations are required. vmtruncate is
deprecated, and truncate_pagecache and inode_newsize_ok helpers introduced
previously should be used.
simple_setattr is introduced for simple in-ram filesystems to implement
the new truncate sequence. Eventually all filesystems should be converted
to implement a setattr, and the default code in notify_change should go
away.
simple_setsize is also introduced to perform just the ATTR_SIZE portion
of simple_setattr (ie. changing i_size and trimming pagecache).
To implement the new truncate sequence:
- filesystem specific manipulations (eg freeing blocks) must be done in
the setattr method rather than ->truncate.
- vmtruncate can not be used by core code to trim blocks past i_size in
the event of write failure after allocation, so this must be performed
in the fs code.
- convert usage of helpers block_write_begin, nobh_write_begin,
cont_write_begin, and *blockdev_direct_IO* to use _newtrunc postfixed
variants. These avoid calling vmtruncate to trim blocks (see previous).
- inode_setattr should not be used. generic_setattr is a new function
to be used to copy simple attributes into the generic inode.
- make use of the better opportunity to handle errors with the new sequence.
Big problem with the previous calling sequence: the filesystem is not called
until i_size has already changed. This means it is not allowed to fail the
call, and also it does not know what the previous i_size was. Also, generic
code calling vmtruncate to truncate allocated blocks in case of error had
no good way to return a meaningful error (or, for example, atomically handle
block deallocation).
Cc: Christoph Hellwig <hch@lst.de>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include/linux/fs.h')
-rw-r--r-- | include/linux/fs.h | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index acf6c52..3428393 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2257,6 +2257,10 @@ typedef void (dio_submit_t)(int rw, struct bio *bio, struct inode *inode, loff_t file_offset); void dio_end_io(struct bio *bio, int error); +ssize_t __blockdev_direct_IO_newtrunc(int rw, struct kiocb *iocb, struct inode *inode, + struct block_device *bdev, const struct iovec *iov, loff_t offset, + unsigned long nr_segs, get_block_t get_block, dio_iodone_t end_io, + dio_submit_t submit_io, int lock_type); ssize_t __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, struct block_device *bdev, const struct iovec *iov, loff_t offset, unsigned long nr_segs, get_block_t get_block, dio_iodone_t end_io, @@ -2270,6 +2274,24 @@ enum { DIO_SKIP_HOLES = 0x02, }; +static inline ssize_t blockdev_direct_IO_newtrunc(int rw, struct kiocb *iocb, + struct inode *inode, struct block_device *bdev, const struct iovec *iov, + loff_t offset, unsigned long nr_segs, get_block_t get_block, + dio_iodone_t end_io) +{ + return __blockdev_direct_IO_newtrunc(rw, iocb, inode, bdev, iov, offset, + nr_segs, get_block, end_io, NULL, + DIO_LOCKING | DIO_SKIP_HOLES); +} + +static inline ssize_t blockdev_direct_IO_no_locking_newtrunc(int rw, struct kiocb *iocb, + struct inode *inode, struct block_device *bdev, const struct iovec *iov, + loff_t offset, unsigned long nr_segs, get_block_t get_block, + dio_iodone_t end_io) +{ + return __blockdev_direct_IO_newtrunc(rw, iocb, inode, bdev, iov, offset, + nr_segs, get_block, end_io, NULL, 0); +} static inline ssize_t blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, struct block_device *bdev, const struct iovec *iov, loff_t offset, unsigned long nr_segs, get_block_t get_block, @@ -2342,12 +2364,14 @@ extern int dcache_dir_open(struct inode *, struct file *); extern int dcache_dir_close(struct inode *, struct file *); extern loff_t dcache_dir_lseek(struct file *, loff_t, int); extern int dcache_readdir(struct file *, void *, filldir_t); +extern int simple_setattr(struct dentry *, struct iattr *); extern int simple_getattr(struct vfsmount *, struct dentry *, struct kstat *); extern int simple_statfs(struct dentry *, struct kstatfs *); extern int simple_link(struct dentry *, struct inode *, struct dentry *); extern int simple_unlink(struct inode *, struct dentry *); extern int simple_rmdir(struct inode *, struct dentry *); extern int simple_rename(struct inode *, struct dentry *, struct inode *, struct dentry *); +extern int simple_setsize(struct inode *, loff_t); extern int noop_fsync(struct file *, int); extern int simple_empty(struct dentry *); extern int simple_readpage(struct file *file, struct page *page); @@ -2384,7 +2408,8 @@ extern int buffer_migrate_page(struct address_space *, extern int inode_change_ok(const struct inode *, struct iattr *); extern int inode_newsize_ok(const struct inode *, loff_t offset); -extern int __must_check inode_setattr(struct inode *, struct iattr *); +extern int __must_check inode_setattr(struct inode *, const struct iattr *); +extern void generic_setattr(struct inode *inode, const struct iattr *attr); extern void file_update_time(struct file *file); |